Carbon brush.



UNITED STATES PATENT OEEICE.

NVALTER C. FISH, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NElV YORK.

CARBON BRUSH.

SPECIFECATION forming part f Letters Patent No. 677,348, dated July 2, 1901.

Application led February 28, 1901. Serial No. l19,261. (No model.)

-To @ZZ whom. it may concer-n:

ythe current transmitted to or from the brush.

Heretofore the flexible braided metallic conductor has been attached tothe brush either by soldering it directly to the coppertween the brushand the cable.

plated surface of the brush, or by fastening it in a transverse holedrilled through the brush, or by clamping and soldering it to a metallicclip, which is then inv turn soldered to the copper-plating of thebrush. The first method is unreliable owing to the diiculty of making amechanically-strong joint be- The second method is objectionable becausethe unequal expansion of the pig-tail and the carbon brush loosens thejoint. The third method is satisfactory, but somewhat expensive.

My invention aims to cheapen the cost rof a reliable brush andconnection without encountering the difficulties attending the olderforms. I omit the metal clip and attach the cable directly to the brushin an open slot or notch cut in the end or edge of the brush. Bycopper-plating the notchthe cable can be readily soldered in place, andasubsequent copper-plating conceals the joint and makes a goed electricalconnection and, aided by the walls of the notch, a strong mechanicaljoint. The open notch permits afree expansion without loosening thejoint.

In the accompanying drawings, Figure 1 shows a carbon brush. Fig. 2shows the brush with an open slot or notch cut in the upper end. Fig. 3shows the same copperplated. Fig. t shows the cable soldered into thenotch. Fig. 5 shows the joint led smooth. Fig. 6 shows the brush groundto gage. Fig. 7 shows the completed copper-plated brush.

Fig. 8 shows the cable secured in a notch in the side of the brush.A

The brush A is a rectangular block of car bon molded or cut toapproximately the proper size. The first step in my process is to cut anopen slot or notch B either transversely across the end of the brush, asin Fig. 2, or longitudinally along one edge or side thereof, as in Fig.8. The notch is of asuitable width to receive the end of a IieXiblenon-resilient braided metallic wire conductor C, commonly called apig-tail, the bottom of the notch being preferably rounded to iitandsupport the circular conductor. After the notch is cut the upper end ofthe brush is electroplated with copper or other good conducting metal D,as shown in Fig. 3. The end of the cable C is then fastened to thecopper-plating in the notch by solder E, which solidly fills the notch,as shown in Fig. 4c, and unites irmly with the thin film of copper D.The surplus solder is then filed off, as shown in Fig. and the brush isfiled or ground or otherwise dressed off to bring it to standard gage inwidth and thickness, as indicated in Fig. 6. As this step in the processremoves v some of the copper-plating, the brush is then replated, asshown in Fig. 7, the copper covering and concealing the joint betweenthe cable and the brush and making a neat-look ing article, besidesaffording a good electrical connection between the brush and the cable.The end of the cable is iirmly supported by 'the walls of the notch,making a strong mechanical joint. This process is simple, expeditious,and cheap, saving from two to three cents per brush over such methods aswere formerly known to me. That a mechanically-strong joint is formed isproved by the fact that a portion of the carbon around the end of thecable will break 0E with the latter if the pig-tail is purposelysubjected to a severe strain. u

In the modification shown in Fig. 8 the cable is brought out parallelwith the length of the brush. This location ygives amuch longer grooveor slot in which to fasten the brush, strengthening the joint andreducingV Furthermore, the

its electrical resistance.

brush-holder does not have to be slotted down one side to permit thebrush to feed down, as

is the case when the cable projects laterally. What I claim as new, anddesire to secure by Letters Patent of the United States, is- 1. A carboncomrntatorbrush having an openv notch, and a iiexible conductor laidlong'itudinally and fastened in said notch.

4. A carbon commutator-brush having an open slot, a flexible conductorreceived longitudinally in said slot, and a mass of solder i coveringsaid conductor. l

V5. A carbon commutatorfbrush having an open notch, a iexible .conductorreceived longitudinally in said notch, and a mass of solder l fill-ingsaid notch.

6. A carbon commutator-brnsh having an open notch, a flexibleconductorreceived longitudinally in said notch, and a mass of solder in saidnotch and flush wit-h the sides thereof. '7.V A carbon brush hav-ing anopen notch 'V whose surface is electroplated, and aiexible conductor incontact with said surface.

, 8. A carbon brush having an open notch whose surface is electroplated,and a iiexible conductor fastened against said surface.

9. A carbon brush having anV open notch with an electroplated surface,and a flexible l conductor soldered to said surface.

10. A carbon brush having an open notch with an electroplated surface, aflexible conductor received in said. notch, and a mass of solder4covering said conductor and united with said surface.

o 1l. A carbon brush having an open notch with an electroplated surface,a flexible conductor received in said notch, and a mass of solderfilling the notch and flush with the sides of the carbon. l

12. A carbon brush having an open notch I with an electroplated surface,a flexible conductor in said notch, a mass of solder filling the notchand fastening the conductor, and

a film of electroplating covering .the joint. 13. A copper-plated carbon.commutator-` i gether.

brushy having a braided-Wire conductor laidy vin said brush, and acoating of copper plate covering Vthe joint and the upper part of thebrush. f l

15. The method of connecting a flexible conductor with a carbon brush,which consists in notching the brush, electroplating the surface of thenotch, laying the conduc tor in the notclnand soldering the two to'- 16.The'method of connecting a flexible Vconductor with a carbon brush,which consists in making a notch in the brush, electr' plating thesurface of the notch, laying the conductor .in the notch, and fillingthe notch with solder.

17. The method of connecting a flexible conductor with a carbon brush,which con--- sists in making a notch in the brush, electroplating thesurface of the notch;- laying the conductor in the notch, filling `thenotch with solder, and making the solder flush with the sides ofthebrush,

18. The method of connecting a fiexible conductor with a carbon brush,which coni sists in notchin g the brush, electroplating the notch,lay-ing the conductor therein, filling p the notch with solder, anddressing off the 1 'solder and the brush to a gage.

r19. The method .of connecting a flexible conductor with a .carbonbrush, which consists in notching the brush, electroplating the notch,laying the conductor therein, filling the notch with soldendressing offthe solder `,and the brush, andjelectroplating them to cover the joint.

20. The combination with la carbon com.- mntator.brush, Of a flexibleconductor laid longitudinally and fastened in :a notch in a side of thebrush, and extending therefrom in a line lengthwise of the brush.

In Witness whereof I have hereunto set my hand this 20th day ofFebruary, 1901.

WALTER C. FISH.

Witnesses:

DUGALD MCK. MoKILLoP, JOHN J. WALKER.

